A display screen, such as a TV, a computer screen or a smart phone, is for displaying image frames. With the rise of demand of display screens, the producing yield becomes increasing.
The display screen illustrates a screen by emitting light in a manner that red light, green light and blue light are controlled and adjusted to generate all kind of variety of colors on the screen. For example, a true color of the display screen is provided by setting each of red light, green light and blue light into 256 degrees in luminance so as to combine the above three kinds of light to become 16777216 colors.
In order to determine the quality of the display screen, the regulation is formulated by the industry of the display screen to establish a standard for inspecting of liquid crystal displays. It includes the criterion of luminance, luminance uniformity, color uniformity, contrast, color chromaticity, color gamut, color tracking, response time and gamma.
The regulation, applied in inspecting method, is too strict to practice in a producing line. For example, the inspecting method for the luminance is regulated to inspect in a darkroom where an environmental leakage light should be less than 2 lux. For this, the display screen must be moved to a darkroom for inspection. Further, the inspection for the luminance uniformity is regulated to inspect a plurality of light points, so an inspector must change the inspecting position to inspect different light points by using the conventional lux meter. And each manual inspecting position will be varied. Furthermore, the inspection for color chromaticity and color uniformity is required to be inspected by processing several kinds of colors of light by using lux meters with different wavelength light, and it thus increases complexity for inspection.